|
|
Article: Embedded passives: debut in prime time: wherever there is a strong need for improved electrical performance, space reduction, EMI reduction or reliability improvement, utilization of embedded passives will be found.(EMBEDDED MATERIALS)
- Article from:
- Printed Circuit Design & Fab
- Article date:
- October 1, 2009
- Author:
CopyrightCOPYRIGHT 2009 UP Media Group, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
The foundation of embedded capacitance in printed circuit boards (PCBs) started in the late 1960s. In U.S. Patent No. 3,519,959, the concept of embedded distributed capacitance (closely-spaced power and ground planes for power supply &coupling) was disclosed. In the patent, two layers of embedded distributed capacitance were used. Each embedded distributed capacitor utilized 0.0025-inch thick epoxy glass and two-ounce (0.0025 inch) copper. The use of even thinner and higher performance embedded distributed capacitance material is disclosed in U.S. Patent No. 4,560,962, filed in 1983. In this case, one-ounce (0.0014 inch) power and ground planes separated by epoxy-glass ...